Fuel-ignition apparatus for internal-combustion engines



Spt; 16 192%. womm w. RIEHM UEL IGNITION APPARATUS FOR INTERNALCOMBUSTION NGINES Filed Aug. 24. x92:

INVENTOR XDW M z t W M/ A 7TORNE Y5 Patented Sept. 16, 1924.

UNITED STATES "1,508,476 earner- 'oF icE;

WILHELM RIEHM, OE AUGSBURG, GERMANY, ASSIGNOR TO THE FIRM; MASCHINEN-FABRIK AUGSBURG-NUERNBURG, AKTIENGESELLSGHAFT, OF AUGSBURG, GER- MANY, AGERMAN CORPORATION.

FUEL-IGNITION APPARATUS FOR INTERNAL-COMBUSTION ENOINES.

Application filed August 24, 1921. Serial No. 494,884.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. 1].,1313.)-

ToaZZ whom it may concern:

Be it known that I, WILHELM RIEHM, a citizen of the German Republic,residing at Augsburg, Germany, have invented certain new and usefulImprovements in Fuel- Ignition Apparatus for Internal-Combus tionEngines (for which I have filed application in Germany, July 25, 1919),of which the following is a specification.

The present invention relates to apparatus for the solid injection offuel into the cylinders of internal combustion engines, andrelatesparticularly to Diesel or similar engines in which the air in thecylinders is highly compressed before the fuel is injected.'

'In engines'of this type it is common to employ a high pressure pump forinjecting the fuel into the cylinder through an atomi'zing noz zle. Insuch a system, however, considerable difficulty has been experienced byafter-flow orgdripping of the fuel into the cylinder after the fullinjection pressure has been exerted by the pump. Thisdripping occurs dueto the fact that the passage between the injection valve and thepressure valve at the pump is filled with fuel which is not forced outduring the stroke of the pump'but which subsequently dripsout duepartially to the reaction of the flexible walls of the oil passage andchiefly because of compressed air from the cylinder making its way upinto this passage. 1

. It has been proposed to place the pressure valve of the pump veryclose to the injection valve so that the volume of the fluid passagebetween the two valves is small. Such an arrangement serves onlyto limitthe quantity of fuel which will drip into the cylinder, since all theliquid contained in the passage between the two valves will drain out asbefore. To avoid this it has been proposed to employ the injection valveof the cylinder simultaneously as a pressure valve of the pump. Now .atthe starting of the engine the oil passage between the injection valveand the pressure valve is normally filled with air. This air iscompressed at the pressure stroke of'the pump piston and expands againat the following suction stroke, thereby forcing back the delivered oilfrom the passage to the pump casing.

It is accordingly a principal object of the present invention to providea fuel injection apparatus for internal combustion engines which avoidsthe above difficulties and at the same time does not interfere in anyway with the normal operation of the engine, and which does not requirespecial parts .or otherwise add to the complication or cost of theengine. This is attained by providing besides the combined injection andpressure valve adjacent the cylinder of the engine, a pressure valve atthe pump which is operative only during the starting of theengine toprevent a back=flow of the oil from the passage to the pump, and whichmay be rendered inoperativewhen the engine is running and the oilpassage is totally filled with oil.

I have illustrated a preferred embodiment of my invention in theaccompanying drawing, which is an elevational view, partly in sectionand largely diagrammatic, of an engine cylinder and itsfcoope'ratinginjection apparatus embodying my invention.

Referring to the drawing a indicates the injection pump or similardevice for forcing liquid fuel into the engine cylinder 9 through theconnecting passage f. At the opening ofthefuel passage f into the enginecylinder there is provided a combined pressure and injection valve 0,here shown diagrammatically as a simple. valve mounted upon a verticalstem and normally 'retained in closed position by means of a coil springh. This valve, however, may be of any desired type adapted to injectfuel into the cylinder and to be closed at the end of the injectionperiod.

At the starting of the pump the oil pas sage f is filled to a largeextent with. air. This air is compressed during the pressure stroke andthen expands owing to its elasticity during the suction stroke of thepump, thereby disturbing the regular operation of the pump. To avoidthis a pressure valve 0? is located at the pump and this \alve isoperative during the starting of the pump so as to prevent the return offuel from the sure valve should be rendered inoperative. Anyconvenientmeans may be employed for pump casing. lVhen the engine is running undernormal conditions, however, this pres- I this purpose, but I haveillustrated a plunclaims without departing from the spirit of ger or arod 6 having its end which is within-the compression chamber of the pumpa inclined upwardly at is and bearing against the lower end of the valvestem (5. Thus when the plunger 6 is moved to its innermost position,asshown, the valve (Z will be; closed. An outward movement of theplunger which may be effected from the exterior of the pump by graspingthe outer end of the plunger, causes the base'of the valve stem to rideup on the'inclined portion 7a of the plunger and hold the valve 03permanently in its open position so that it has no effect upon the flowof the fluid. Valve 0 thus is the only valve which functions during theinjection of fuel into the cylinder.

I have illustrated a preferred embodiment of my invention, but it is tobe understood that the form of the valves, the various means of control,and the like, may be varied within the full scope'of the. appended theinvention.

I I claim: 1. In a fuel injection apparatus for internal combustionengines, the combination with a fuel pump for injecting fuel into theengine cylinder at highpressure and a passage connecting the pump withthe cylinder, of a combined injection and pressure valve adjacent theengine cylinder for spraying the pumped oilinto the cylinder andfor-preventing return-flow of oil to the passage, and'a pressure valvelocated at the pump and adapted to be'rendered operative only duringthe'starting of the engine when the passage containsair, and when sooperative serving to prevent the return of oil from the passage into thepump.

rsoaeve 2. In a fuel injection apparatus for internal combustionengines, the combination with a fuel pump for injecting fuel into theengine cylinder at high pressure, and a pas: sage connecting the pumpwith the cylinder 'of a combined injection and pressure valve adjacenttheengine cylinder for spraying the pumped oil into the c linder and forpreventing return flow of oil to the passage and a manually operatedvalve located at the pumpand adapted to be rendered operative onlyduring the starting of the engine, when the passage. contains air, andwhen so operative serving to prevent the return of oil from the passageinto the pump during the suction stroke of the pump, the valve at alltimes permitting the flow of oil from the pump to the cylinder. I

3. In a fuel in ection apparatus for internal combustion engines, thecombination with a fuel pump for injecting fuel into the engine cylinderat high pressure and a pasvalve at all times permitting the fiow of oilfrom the pump to the cylinder.

In witness whereof I aflix my signature.

DR. WILHELM RIEHM.

